University of Hawaii, Department of Oceanography, 1000 Pope Road, Honolulu, HI 96822, USA.
Appl Environ Microbiol. 2011 Aug;77(15):5384-93. doi: 10.1128/AEM.02509-10. Epub 2011 Jun 3.
We investigated the abundance, distribution, and virulence gene content of Vibrio cholerae, V. parahaemolyticus, and V. vulnificus in the waters of southern Lake Pontchartrain in Louisiana on four occasions from October 2005 to September 2006, using selective cultivation and molecular assays. The three targeted pathogenic vibrios were generally below the detection level in January 2006, when the water was cold (13°C), and most abundant in September 2006, when the lake water was warmest (30°C). The maximum values for these species were higher than reported previously for the lake by severalfold to orders of magnitude. The only variable consistently correlated with total vibrio abundance within a single sampling was distance from shore (P = 0.000). Multiple linear regression of the entire data set revealed that distance from shore, temperature, and turbidity together explained 82.1% of the variability in total vibrio CFU. The log-transformed mean abundance of V. vulnificus CFU in the lake was significantly correlated with temperature (P = 0.014), but not salinity (P = 0.625). Virulence-associated genes of V. cholerae (ctx) and V. parahaemolyticus (trh and tdh) were not detected in any isolates of these species (n = 128 and n = 20, respectively). In contrast, 16S rRNA typing of V. vulnificus (n = 298) revealed the presence of both environmental (type A) and clinical (type B) strains. The percentage of the B-type V. vulnificus was significantly higher in the lake in October 2005 (35.8% of the total) than at other sampling times (P ≤ 0.004), consistent with the view that these strains represent distinct ecotypes.
我们在 2005 年 10 月至 2006 年 9 月的四次调查中，使用选择性培养和分子检测方法，研究了路易斯安那州南庞恰特雷恩湖水域中霍乱弧菌、副溶血性弧菌和创伤弧菌的丰度、分布和毒力基因含量。在 2006 年 1 月水温较低（13°C）时，这三种目标致病性弧菌通常低于检测水平，而在 2006 年 9 月水温最高（30°C）时最为丰富。这些物种的最高值比以前报道的湖泊值高出几个数量级。在单个采样中，唯一与总弧菌丰度始终相关的变量是离岸边的距离（P = 0.000）。对整个数据集的多元线性回归显示，离岸边的距离、温度和浊度共同解释了总弧菌 CFU 变化的 82.1%。湖中创伤弧菌 CFU 的对数平均值与温度呈显著相关（P = 0.014），但与盐度无关（P = 0.625）。未在这两种弧菌的任何分离株中检测到霍乱弧菌（ctx）和副溶血性弧菌（trh 和 tdh）的毒力相关基因（分别为 128 株和 20 株）。相比之下，创伤弧菌的 16S rRNA 分型（n = 298）显示出既有环境（A 型）又有临床（B 型）菌株。2005 年 10 月湖中 B 型创伤弧菌的比例（占总数的 35.8%）明显高于其他采样时间（P ≤ 0.004），这与这些菌株代表不同生态型的观点一致。
